3D-Printed Organ-on-Chip Models of the Human Blood-Brain Barrier: A Platform to Study BBB Function and Drug Permeability

The blood-brain barrier (BBB) is a key functional component of the neurovascular unit (NVU), which comprises endothelial cells, pericytes, astrocytes, and neurons. The NVU tightly regulates molecular exchange between the bloodstream and the central nervous system, maintaining brain homeostasis. Given the complexity of its anatomical structure, it’s complicated to identify specific cells responsible for adverse stimuli, particularly in the context of single-cell cultures as well as the mechanisms underlying pathological conditions. Traditional in-vitro models and animal studies fail to fully recapitulate the cellular architecture and dynamic environment of the human brain. These limitations, and ethical concerns, have accelerated the search for advanced human-relevant models. Organ-on-a-chip (OoC) technology offers an advanced approach to recreate human barrier physiology under controlled conditions. Here, we present two biocompatible, stereolithography-based 3D-printed OoC platforms, capable of modelling the human BBB and investigate cell-cell interactions, barrier integrity, and transport properties. The first device features two chambers separated by a porous membrane, with independent inlets and outlets for perfusion. Human endothelial cells and neuronal cells were co-cultured, barrier function assessed via in situ trans-endothelial electrical resistance (TEER), cell viability and function were confirmed via immunofluorescence and live calcium imaging. The second platform consists of a single open chamber, allowing the co-culture of endothelial cells (top surface), and neurons. The chip was designed to apply controlled flow and shear stress, enabling studies of how hemodynamic forces in the vascular lumen impact BBB integrity and trigger BBB dysfunction. Unlike PDMS-based devices, these 3D-printed models offer rapid prototyping, avoiding absorption of hydrophilic substances, and flexible sensor integration, such as TEER electrodes for real-time monitoring. In summary, we present two modular, biocompatible BBB-on-chip platforms capable of supporting multicellular BBB cultures, real-time functional assessment, and drug screening. These tools provide a physiologically relevant alternative to animal models and represent a promising platform for investigating BBB dysfunction and CNS drug delivery.